Utilise execversion to one-time reset two cvars on upgrade to v1.4.

- `cv_masterserver` - Replaces a hack checking for the original SRB2 MS addres every time, and additionally catches those who tested an early version of the http MS.
- `cv_usegamma` - This was previously WAY too easy to accidentially change. This way, a user who has had this accidentially happen will automatically return to baseline.

src/command.c

@@ -1884,6 +1884,13 @@ static boolean CV_FilterVarByVersion(consvar_t *v, const char *valstr)
 	if (!(v->flags & CV_SAVE))
 		return true;
 
+	if (GETMAJOREXECVERSION(cv_execversion.value) < 8) // 8 = 1.4
+	{
+		if (!stricmp(v->name, "masterserver") // Replaces a hack in MasterServer_OnChange for the original SRB2 MS.
+			|| !stricmp(v->name, "gamma")) // Too easy to accidentially change in prior versions.
+			return false;
+	}
+
 	if (GETMAJOREXECVERSION(cv_execversion.value) < 2) // 2 = 1.0.2
 	{
 #if 0

src/mserv.c

@@ -554,17 +554,6 @@ static void MasterServer_OnChange(void)
 #ifdef MASTERSERVER
 	UnregisterServer();
 
-	/*
-	TODO: remove this for v2, it's just a hack
-	for those coming in with an old config.
-	*/
-	if (
-			! cv_masterserver.changed &&
-			strcmp(cv_masterserver.string, "ms.srb2.org:28900") == 0
-	){
-		CV_StealthSet(&cv_masterserver, cv_masterserver.defaultvalue);
-	}
-
 	Set_api(cv_masterserver.string);
 
 	if (Online())